sample rate


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sample rate

(digital signal processing)
The number of times an analog signal is measured (sampled) per second. The unit of sample rate is "samples per second". This is often expressed in kiloHertz (kHz). For example, "CD quality" sound has a sample rate of 44 kHz.

Compare data rate. See Nyquist frequency.

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

high-resolution sampling rates

Following is a list of common digital sample sizes and sampling rates for high-quality audio. See high-resolution audio, DSD and high-resolution audio sources.

Sample                         Stereo  Size     Sampling Rate       Transfer (Bits)  Samples Per Second      Rate

   16     44,056 (44.1 kHz)**  1409 kbps

   16     48,000 (48 kHz)      1536 kbps

   24     88,200 (88.2 kHz)    4234 kbps

   24     96,000 (96 kHz)      4608 kbps

   24    176,400 (176.4 kHz)   8467 kbps

   24    192,000 (192 kHz)     9216 kbps

   24    384,000 (384 kHz)    18432 kbps


   Compressed MP3 files (for comparison)

           Common MP3 file:    128 kbps

           High-res MP3 file:  320 kbps


   ** Standard music CD (see  CD-DA)

sampling

(1) In statistics, the analysis of a group by determining the characteristics of a significant percentage of its members chosen at random.

(2) Converting analog signals into digital form. Audio and other analog signals are continuous waveforms that are analyzed at various points in time and converted into digital samples. The accuracy with which the digital samples reflect their analog origins is based on "sampling rate" and "sample size." See A/D converter.

Sampling Rate - When to Measure
The sampling rate is the number of times per second that the waveform is measured, which typically ranges from 8 to 192 thousand times per second (8 kHz to 192 kHz). The greater the rate, the higher the frequency that can be captured. For a comparison of high-quality samples, see high-resolution sampling rates.

The sampling rate must be at least twice that of the analog frequency being captured. For example, the sampling rate used to create the digital data on a CD is 44.1 kHz, slightly more than double the 20kHz frequency an average person can hear. The sampling rate for digitizing voice for a toll-quality conversation is typically 8,000 times per second (8 kHz), twice the 4 kHz required for the full spectrum of the human voice. See analog and Nyquist theorem.

Sample Size - The Measurement
Also called "resolution" and "precision," the sample size is the measurement of each sample point on a numeric scale. Known as "quantizing," the sample point is turned into the closest whole number. The more granular the scale (the more increments), the more accurate the digital sample represents the original analog signal. See oversampling, quantization and PCM.


Sampling Sound
The faster the sampling rate and the larger the sample size, the more accurately sound can be digitized. An 8-bit sample breaks the sound wave into 255 increments compared with 65,535 for a 16-bit sample.







Sampling Dialog
This recording dialog from an earlier Sound Blaster sound card shows typical sampling options for digitizing sound into Windows WAV files.







DSD - A High-Res Sampling Technique
Direct Stream Digital (DSD) is a dramatic departure from PCM. Instead of turning samples into a number with a range of values, DSD samples are only 1-bit long (0 or 1), depending on whether the wave is moving up or down from the previous sample point (see DSD).
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References in periodicals archive ?
To illustrate, assume the digitizer's maximum sample rate is 100 MS/s, which makes its Nyquist frequency 50 MHz, and the signal has two components: the fundamental at 10 MHz and a spur frequency component at 20 MHz.
it has also gone from a 16 kHz sample rate per second to a sample rate of 32,000 samples per second.
If the formula is applied to an ideal Arb with a sample rate of 4 GS/s and 8-b resolution, then SNR will be around 73 dB.
Once restricted to advanced users with specialized needs for long time capture, deep memory products are now appreciated more generally for the sample rate and display quality benefits they bring to everyday design and debug tasks.
The new Dante expansion card introduces per-card sample rate conversion, which allows several independent audio networks that run on individual clocks and sample rates to be connected to and unified in a single Penta 720 or AX32.
Table 2 lists the reconstruction times for different schemes at different sample rates. When the total sampling rate S is 0.1, the execution time of our method is close to that of MH_SPL for different test images, but much less than those of NESTA and DPCM + NESTA.
The ADAU1452 features a 1.2-volt, 32-bit DSP core that runs at frequencies up to 294.912 MHz and executes up to 6,144 instructions per sample (the approximate equivalent of 1.2 GMAC/s or 295 MIPS) at the standard sample rate of 48 kHz.
As we have seen in the above analysis, the minimal sample rate of the signal x(t) is 2L/[tau], which is usually much lower than Nyquist sampling rate.
The number of samples depends on the amount of monitoring time and the sample rate used to capture the packets.
The new high definition oscilloscopes (HDOs) are available in two series, the HDO4000 and HDO6000, which acquire waveforms with high resolution, high sample rate and low noise.
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